The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.

On January 19, 2006, the Pluto-New Horizons spacecraft was launched from Cape Canaveral Air Force Station (CCAFS) with a radioisotope thermoelectric generator (RTG) as the power source and a 30V power regulation and distribution system designed and built by the Johns Hopkins University Applied Physics Laboratory. Pluto-New Horizons is the flagship spacecraft of NASA's New Frontiers program of medium-class interplanetary missions and targets the first reconnaissance of Pluto and its moon, Charon, and the Kuiper Belt. Arrival at Pluto is scheduled for July, 2015 at which time the spacecraft will have traveled 3 billion miles and be almost 32 AU from the sun. Due to the extended mission duration and extreme distance from the sun, a RTG was chosen as the spacecraft's power source. RTG missions place complexity on the spacecraft power system design due to their unique power characteristics and limited opportunities for test prior to pre-launch field operations. The RTG integration and test with the spacecraft results are presented along with the spacecraft power system performance during launch and in the early mission phase. These in-flight operational results demonstrate a fully functioning power system that will supply the spacecraft with safe and reliable power during the exploration of the farthest reaches of the solar system.

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The NASA New Horizons mission to the Pluto system and the Kuiper